Apparatus for spinning solutions of cellulose ethers or esters



MELITTA xLEi v, or VIENNA,

Patented June 24, 1930 PATENT OFFICE v AUSTRIA, ASSIGNOR T0 RUTH-ALDOCOMPANY, INC.,

OF NEW YORK, N. Y.

APPARATUS FOR SPINNING SOLUTIONS OF CELLULOSE ETHERS OR ESTERSApplication filed March 27, 1928, Serial No. 265,158, and in France June22, 1927.

It is known that the spinning of cellulose ethers and esters is carriedon in closed chambers or cells, in order to facilitate the collectionand recovery of the volatile solvents employed.

It is also known that, with a view to ffiCllltating the evaporation ofsaid solvents, sa d chambers or cells are usually heated by sultablemeans.

These arrangements are not a source of inconvenience when the spinningproceeds from below upwards, but, on the contrary, when the spinningproceeds from above downwards, the spinning nozzle is disposed right inthe top part of the chamber or cell and thus in the hottest zone, thetemperature of which upper zone is very high. Under these conditions,the cellulose issuing from the spinning nozzles is suddenly raised tothis very high surrounding temperature, the effect of which is either toincrease the fluidity of the spinning material and lower its viscosity,or to set up rapid evaporation of the solvent.

In all cases the resulting threads are defective and of inferiorquality.

1 the chamber, in such a way that the cold air,

drawn towards the centre of the chamber, flows in a downward directionwhereby the threads, as they issue from the spinning nozzle, areSubJected to a cold circumambient medium.

However, in order that this arrangement may be completely eflicacious,it is necessary to prevent airy considerable amount of hot air ascendingfrom the bottom of the cell into the top. With this object, according tothe invention, a diaphragm is disposed, at a suitable height, so as todivide the interior of the cell into two compartments and is mounted insuch a way as to allow of the passage of the threads.

If, with a device of this kind, the aspiration drawing the air'ladenwith vapours of solvents from the cell into the recovery apparatus isproperly regulated, the hot" air will not reascend from the zone belowthe diaphragm into the upper zone, but on the contrary, the cold air ofthe upper zone will be drawn through the hole provided, in thediaphragm, for the passage of the thread; and this cold air will passinto the lower zone, thereby facilitating the passage of the thread.In'this manner the spinning nozzle and the first portion of the pathtraversed by the thread can be maintained at the same temperature astheoutside air.

By way of example, a description will now be given of a spinning chamberprovided with the improvements the principle of which has just beenenunciated.

In the accompanying drawing, Fig. 1 is a vertical section through saidchamber, Fig. 2 a plan of same, Fig. 3 a partial vertical sectionshowing the diaphragm in the open position, and Fig. 4: a plan of thediaphragm.

Holes EE E are pierced in the top AB of the cell ABCD, for the admissionof cold air. These holes, in convenient number, may be disposedcircularly round the spinning nozzle F, situated in the centre of thetop AB of the cell. The thread, represented diagrammatically by H,travels from above downwards and winds on the bobbin I located in thelower part of the cell. The aspiration is preferably eflected on a levelwith said bobbin I.

The diaphragm is indicated at MN. In the example under consideration,the diaphragm' is horizontal, and is composed of two portions, namely afixed member MP, and another member PN adapted to pivot on a hinge P andresting, byv means of its edge N, on a projection 0 carried by the wallAC of the cell.

As can be seen in Fig. 4, the pivotal member PN of the diaphragm isprovided with a notch TRS of such a shape that, when the apparatus isstarted, in commencing to spin, the movable member PN can be lowered andstill leave room for the passage of the thread. In order to start theapparatus, this movable member is raised into the po-- sition shown inFig. 3.

After theapparatus is started, the triangular notch TBS is closed, by aneasily constructed and simple device, consisting of a sliding orrotating member, in such a way that onlythe small aperture necessary forthe passage of the thread is left open in the diaphragm.

The heating may be efiected in any part whatsoever of the zone beneaththe diaphragm. I

The device affords the advantage of keeping the first portion of thethread in continuous contact with cold air, this latter. merelyabsorbing the vapours (of the solvents) liberated in this first portionof the path of the thread. On the other hand, in the absence of adiaphragm, this portion of the thread travels in hot air, and, in thecase of solvents whose vapours are lighter than air, is surrounded by anatmosphere highly charged with vapours.

Certain operations, such as drawing or stretching, can be carried out,under particularly favourable conditions, in a vapourladen medium. Thepresence of the diaphragm enables the intermediate and final portions ofthe ath of the thread to be precisely subjecte to these favourableconditions;

Finally, it will be understood that it is possible (and evenadvantageous in certain cases) to provide not only a single diaphra mbut a plurality of diaphragms, dis pose thread. These enable thetemperature, or the density of the vapours with whichfthe air is laden,to be regulated, according to requirements, at various levels in thecell.

I claim:

1. Apparatus for use in spinning artificial thread, comprising aspinning cell, means dividing the interior of the cell into superimposedzones adapted to be traversed successively by the spun thread, aspinning nozzle in the upper zone, means for admitting air to theuppermost zone about the spinning nozzle, and means'whereby hot air andsolvent vapours can be drawn from the lowermost zone.

2. Apparatus for use in spinning artificial thread, comprising aspinning cell, at least one diaphragm dividing the interior of the cellinto superimposed zones adapted to be traversed by the spun thread, adownwardly directed splnning nozzle in the upper zone,

means for admitting air to the upper zone about the spinning nozzle, andmeans,

whereby hot air and solvent vapours can be drawn from the lower zone.

3. Apparatus for use in spinning artificial thread, comprising aspinning cell, at least one diaphragm dividing the interior of the cellinto superimposed zones adapted to traversed by the spun thread, adownwardly directed spinnin nozzle in the u per zone said diaphragm einconstituted y a fixed member and a notcied, movable member, means foradmitting air to the up er zone about the spinning nozzle, an meanswhereby hot air and solvent vapours can be drawn from the lower zone.

' 4. Apparatus for use in spinnin artificial threads, comprising aspinning ce a downwardly directed spinning nozzle in the upper part ofthe cell, means for admitting cold air about the spinning nozzle and thethread issuing therefrom, and at least one diaphragm in the cellextending partly over the area thereof.

5. Apparatus for use in spinning artificial thread, comprising aspinning cell, a downwardly directed spinning nozzle in the upper partof the cell, means for admitting cold air about the-spinning nozzle andthe thread issuing therefrom, at least one diaphragm in the .cellextending artly over the area thereof, and means w ereby hot air andsolvent vapours can be drawn from the lower part of the cell below thediaphragm.

In testimony whereof I aflix my signature.

MELITTA KLEIN.

at various points in the path ofthe

